Ship for carrying liquid cargoes in bulk.



H.'LAING & E. W. ASHBY.

SHIP FOR CARRYING LIQUID CARGOES IN BULKr APPLICATION FILED ocT. al. 1916.

1,234,675. Patented July 24, v1917. 2 SHEETS-SHEET I.

m a @l Zw G H/ i@ X fg a. I l 5 I l H. LAING & E'. W. ASHBY.

SHIP FOR CARRYING LIQUID CARGOES IN BULK.

APPLICATION FILED OCT. 3l |916.

Patented July 24, 1917.

2 SHEETS-SHEET 2 {I/ IIII III H F W.. IIII II I In:

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HUGH LAING AND EDWARD WILKINSON ASIIBY, OF SNDRLAND, ENGLAND.

SHIP FOR CARRYING LIQUID CARGOES IN BULK.

Speccation of Letters Patent. Patented J' 24, 191 "7.

Application filed October 31,- 1916. Serial N0.y 128,690.

To all 107mm t may concern:

Be it known that we, HUGH LAING and EDWARD TILKINSON ASHBY, subjects of the King of Great Britain and Ireland, residing in Sunderland, in the county of Durham, England7 have invented certain new and useful Improvements in Ships for Carrying Liquid Cargoe's in Bulk, of which the following is a specication.

This invention relates to the special type of ships known as tankers which are used for carrying liquid cargoes in bulk, such, for example, as oil or molasses. In

tankers longitudinal strength is of first importance and the comparatively numerous compartments and close-spaced transverse bulkheads, also the framing and other structural parts, are designed specially and of approved strength to carry liquid cargoes in bulk.

The object of the present invention is to provide an improvedbulkhead construction for tankers whereby increased longitudinal strength and other advantages are obtained. U n

In a liquid cargo carrying vessel of the type known as a tanker in accordance with this invention, we arrange one or more of the transverse bulkheads so that, where a single longitudinal straight-line bulkhead is provided and the cargo space thus divided into two longitudinal compartments, the portions of the transverse bulkheads crossing the compartments `on each side of said longitudinal bulkhead are not in line the one with the other, but are stepped a convenient distance away; and, where two longitudinal straight-line bulkheads are provided and the cargo space divided into three longitudinal compartments,- one or more of the bulkheads crossing the center longitudinal compartment are notV in line with the bulkheads crossing the side longitudinal compartments, but are stepped a convenient distance away.

Ne will fully describe our invention with reference to the accompanying drawings wherein- Figures l and 2 are a profile and a plan of a tanker or vessel designed to 'carry liquid cargoes in bulk, provided with two longitudinal straight-line bulkheads and with transverse bulkheads arranged in accordance with our invention; and

Figs. 3 and fi are transverse sections on the lines a-a'. and respectively inFigs.

In all the figures like letters of reference indicate like parts.Y Y Figs. l,y 2, 8 and 4 illustrate the application of our invention to a vessel having a single deck and two longitudinal bulkheads A, A extending from the after coii'erdam W to the forward cofferdam X and from the bottom to the upper deck of the ship Vbut not above same. Abatt the after cofferdam is the machinery space Z, the machinery being placed above the tank Y. In this eX- ample the cargo space is divided into three longitudinal compartments F which are subdivided by transverse bulkheads G, H. The bulkheads G which cross the center longitudinal compartment are not in line with the bnlkheads H which cross the side longi# tudinal compartments but'are stepped al convenient distance away. vIf desired the side transverse bulkheads H may also bearranged out of line with each other as well as out of line with the center transverse bulkheads G, as will be readily understood without illustration.

Figs. 5, 6 and 7 illustrate the application of our invention to a vessel having tween decks M and a single central longitudinal bulkhead A so that the cargo space is divided into two longitudinal compartments F which are subdivided by transverse bulkheads H. In this case the portions of transverse bulkheads H on each sideof the longitudinal bulkhead A are not in line with each other but are stepped a convenient distance away.

Vith the arrangement of the transverse bulkheads G and H illustrated in Figs. 1 to 7, the longitudinal strength of the vessel at a cross section through any transverse bulkhead G or H crossing a cargo space F is increased because the close-spaced rivet holes in the boundary angles L of the transverse bulkheads do not' extend in line completely around the whole of the side and bottom platingl or across the whole' width of the deck ashas hitherto been customary in tankers, but are stepped on either Vside of the longitudinal bulkhead or bulkheads A, and thus an increased sectional area of ma-l terial to resist the longitudinal stresses is provided without employing any additional material.

The drawings show vessels constructed with close-spaced side shell longitudinal frames Q, and longitudinal deck beams PC, PS, and bottom frames TC, TS and with longitudinal bulkhead stiffeners E, supported by strong comparatively widelyspaced transverse frames or ribs R between the transverse bulkheads, but the ship may be constructed with the usual transverse framing, or with part transverse and part longitudinal framing. Vhere we fit two longitudinal bulkheads the stifeners E are preferably continuous in way of the transverse bulkheads passing uncut across the ends of the transverse bulkheads H, but on the other side thereto of the longitudinal bulkheads A and thus add considerably to the longitudinal strength. In Fig. 8 the deck and bottom longitudinals PC and TC are continuous in way of the transverse bulkheads H and also the longitudinall bulkhead stieners E, while the remaining longitudinals on the shell and deck are cut at these bulkheads. In Figs. 4 and 5 the deck and bottom longitudinals PS and TS toward the sides and the side shell longitudinals Q, are continuous in way of the part transverse bulkheads. Thus, a good proportion of the longitudinal stiffeners pass the part transverse bulkheads uncut and add considerably to the longitudinal strength and efliciency of the ships structure, while a saving of weight is effected by the part bulkheads taking the place of some or all of the longitudinal bulkhead vertical webs.

Transverse wash-plates KCLKS Figs. 3 and 4) or transverse beams RC, RS (Fig. 5) may be fitted below the longitudinal deckbeams FC, PS and in line with the transverse bulkheads G, H. The wash-plates may be attached to the longitudinal deck beams by knee plates and/or suitable lugs thus dispensing with the comparatively widespaced rivet holes through the deck which would be necessary if the said portions were connected directly by ianging or bylugs or with intercostal plates to the deck. The transverse floors RC, RS (Figs. 3, 4 and 5) may also be arranged above the bottom frames TC, TS and attached thereto by knee plates and/or lugs.

l/Vhere the cargo space is divided into three longitudinal compartments F by two longitudinal watertight bulkheads A, A as illustrated in Figs. l to 4 each compartment being about one-third of the vessels beam, the transverse watertight bulkheads G, H subdividing the three longitudinal compartments are spaced at greater intervals than usually approved of by the Classification Societies for liquid cargo-carrying vessels tankers having only a single longitudinal bulkhead.

The three series of tanks formed by the two longitudinal bulkheads A, A (Figs. 1 to 4) being each about one-third of the beam of the vessel in width, form their own eX pansion trunks and permit of the omission` of the usual expansion trunk extending fore and aft amidships above or below the deck, or of any other trunks adapted to limit the extent of the free surface of the liquid cargo or to allow for expansion of the liquid, sufficient spare capacity for the usual expansion of the liquid when the vessel has a full cargo on board being allowed for by our construction.

/Vhere the cargo space is divided into three longitudinal compartments of about equal capacity as illustrated in Figs. l to 4, the e'ect of the free surface of the liquid cargo on the transverse stability of the shipV Y in the worst condition of loading (that is, Y

when free liquid is present in all the tanks at the same time), is much less than that of the case of an ordinary oil tank vessel fitted with one longitudinal bulkhead at the center line with the surface of the liquid some distance below the bottom of the expansion trunk. All the tanks can be filled withV liquid until nearly full, and yet allow sufcient room for expansion, and even then the effect of the free surface of the liquid cargo on the transverse stability would not be such as to endanger the vessel.

)When a ship having two longitudinal bulkheads is loaded with liquid cargo of great Y density and requiring less stowage space, one or more of the central tanks may be entirely emptied while the remaining tanksV may be practically full, and the cargo will thus be more equally distributed than vis possible in a ship having a. single longitudinal bulkhead, and undue straining of the ship is obviated. Y

In some cases where We lit the ship with two longitudinal watertight bulkheads A, A, we may slope the side portions of the upper deck up to the central level portion in a curved or straight line (as in Figs. 3 and 4), or the sides of the vessel may be inclined inward from about the load waterline upto the upper deck, to a greater extent than usual, to limit the widths of the side compartments at the top.

What we claim and desire to secure .by Letters Patent is l. A bulkhead construction for a liquid cargo carrying ship of the type known as a tanker comprising not less than one longitudinal bulkhead dividing the cargo space into longitudinal compartments, and not less than one transverse bulkhead subdividing said longitudinal compartments, the portions of each transverse bulkhead on each side of a longitudinal bulkhead being out of line the one with the other.

2. A bulkhead construction for a liquid cargo carrying ship of the type known as a tanker comprising two longitudinal bulkheads formed in straight lines in the fore and aft direction extending from the bottom of the vessel only to the upper deck and dividing the cargo space into three longitudinal compartments, and not less than one transverse bulkhead subdividing said longitudinal compartments, portions of each transverse bulkhead being out of line the one with the other.

3. A bulkhead construction for a liquid cargo carrying ship of the type known as a tanker comprising two longitudinal bulkheads formed in straight lines in the fore and aft direction dividing the cargo space into three longitudinal compartments, Vand not less than one transverse bulkhead subdividing said longitudinal compartments, portions of each transverse bulkhead being out of line the one with the'other, and close-spaced longitudinal stileners.

4. A bulkhead construction for a liquid cargo carrying ship of the type known as a tanker comprising two longitudinal bulkheads formed in straight lines in the fore and aft direction dividing the cargo space into three longitudinal compartments, and not less than one transverse bulkhead subdividing said longitudinal compartments, portions of each transverse bulkhead being out of line the one with the other, and close-spaced longitudinal stiteners, said longitudinal stiffeners being continuous and arranged on the inner sides of the longitudinal bulkheads.

5. A liquid cargo carrying ship of the type known as a tanker having longitudinal deck beams and a bulkhead construction comprising not less than one longitudinal bulkhead dividing the cargo space into longitudinal compartments, and not less than one transverse bulkhead subdividing said longitudinal compartments, the portions of each transverse bulkhead on each side of a longitudinal bulkhead being out of line the one with the other, in combination Copies of this patent may be` obtained for ve cents each, by addressing the type known as a tanker having longitudinal deck beams and a bulkhead construction comprising two longitudinal bulkheads formed in straight lines in the fore and attl ldirection extending from the bottom of the vessel only to the upper deck and dividing the cargo space into three longitudinal compartments, and not less than one transverse bulkhead subdividing said longitudinal compartments, portions of each transverse bulkhead being out of line the one with the other, in combination with transverse washplates fittedv below said longitudinal deck beams in line with said portions of the transverse bulkheads, said transverse washplates being attached to the longitudinal deck beams.

7. A liquid cargo carrying ship of the type known as a tanker having longitudinal deck beams and a bulkhead construction comprising two longitudinal bulkheads formed in straight lines in the fore and aft f direction dividing the cargo space into three longitudinal compartments, and not less than one transverse bulkhead subdividing said longitudinal compartments, portions of each transverse bulkhead being out of line the one with the other, and close-spaced longitudinal stieners, said longitudinal stiHeners being continuous and arranged on the inner sides of the longitudinal bulkheads, in combination with wash-plates f1tted below said longitudinal deck beams in line with said portions of the transverse bulkheads, said transverse washplates bep ing attached to the longitudinal deck beams.

In witness whereof, we have hereunto signed our names in the presence of two subscribing witnesses.

HUGH LAING. EDWARD WILKINSON ASHBY. l/Vitnesses:

HERBERT HOWARD, WILLIAM DAGGETT.

Washington, D. C. 

